1. Field of the Invention
The present invention generally relates to the field of video conferencing and, more particularly, to a method and apparatus for controlling a video camera in a video conferencing system.
2. Background Information
Video conferencing systems are known in the art. Video conferencing systems are available in a wide range of systems with a corresponding variety of features and capabilities. Personal computer (PC) video conferencing systems, for example, offer a flexible video conferencing solution to the masses. That is, with the addition of a video/sound board and a PC video camera, a standard home/business computer system may be transformed into a video conferencing system, while retaining all of the standard computing capability inherent in the computer system.
Even within the market of PC video conferencing systems, the capabilities and features vary between vendors and between market price points within a vendor""s offerings. For example, the ProShare(copyright) Video Conferencing system from Intel Corporation provides a personal computer with the ability to engage in a video conference with other compatibly enabled computer(s). With the ProShare(copyright) and most other PC video conferencing systems, a video camera sits atop the computer monitor and points in the general vicinity of the local user. In more advanced PC video conferencing systems, the focal length of the local video camera may be controlled by the local user to zoom in/out. That is, the local user may adjust the focal length of the local camera (e.g., zoom in/out) to control the size of the image depicted within the video conference window of the remote video display unit.
Stand alone video conferencing systems (or, dedicated video conferencing systems) are also well known, and also offer a broad range of video conferencing features and capability. In general, many of the stand alone video conferencing systems include camera control systems at either end of the video conferencing system, allowing local users with a remedial ability to manually control the remote video camera.
These prior art systems, however, require that a local user manually adjust the field of focus (e.g., xe2x80x9cpanxe2x80x9d, xe2x80x9csteerxe2x80x9d, or otherwise position) the remote video camera to locate the actual remote speaker, manually xe2x80x9cframexe2x80x9d the speaker (e.g., center the image within the frame of the video window) and adjust the focal length (e.g., zoom) of the remote video camera via some sort of local camera control mechanism (e.g., keyboard control). Novice users of such video conferencing systems find, however, that the camera control mechanism of these prior art conferencing systems are not intuitive or easy to use. They often have a lag time associated with their operation, thereby causing the remote video camera to xe2x80x9covershootxe2x80x9d the desired object when panning to view a particular object. In addition, many of the prior art cameras also required the user to manually focus and/or zoom the camera when the object of interest was ultimately framed. These and other shortcomings of the prior art made their use inefficient, e.g., conference participants spent an inordinate amount of time positioning the camera equipment, causing many potential conference participants to opt for alternative conferencing mediums with which to conduct their conference.
In response, certain manufacturer""s of video conferencing system have introduced automated video camera control systems which obviate the need for manual control by conference participants. Many of these automated video camera control systems rely on a network of distributed microphones to locate a speaking conference participant within a room, and an xe2x80x9cauto-focusxe2x80x9d camera system to ensure the clarity of the picture. One such prior art system is disclosed in U.S. Pat. No. 5,206,721 to Ashida, et al. and commonly assigned to Fujitsu Limited. Those skilled in the art will appreciate that such prior art systems suffer from a number of inherent limitations.
First, the accuracy of these automated video camera control systems are greatly dependent upon the number of microphones used in the system and the distribution of these microphones, and the number of video conference participants. That is, if the video conferencing station has only two microphones, the accuracy of the automated video camera controller is quite limited, even if the microphones are widely distributed (e.g., opposite sides of the room). Second, the accuracy of these prior art automated camera control systems is inversely related to the number of conference participants. That is, the accuracy of the automated camera control systems is diminished as the number of simultaneous speakers increases.
Thus, an improved camera control system is needed that is unencumbered by the deficiencies and limitations commonly associated with the prior art.
In accordance with the teachings of the present invention, a method and apparatus for the control of a remote video camera is disclosed. In a first example embodiment of the present invention, an innovative video conference station is disclosed comprising an image analyzer and a camera controller. The image analyzer receives video frames from a communicatively coupled first camera, detects the head of one or more conference participants within the received video frames and detects an active participant from the one or more conference participants. The camera controller, coupled to the image analysis circuit, controls a second camera based, at least in part, on detecting the active participant.